Various tissue engineering strategies have been adopted to treat damaged heart muscle as a result of myocardial infarction. However, the rebuilt myocardium must include a vascular network able to nourish it under diverse metabolic demands. Recently we demonstrated the efficacy of such an approach using cardiac tissue grafts developed from genetically modified mesenchymal stem cells. While demonstrating the value of such an approach, a better source of cells for tissue engineering would be induced pluripotent stem cells (iPSCs) derived from the patient's own tissues. Our objective is to develop a novel approach to treatment of myocardial infarction (MI), using a rodent model, that involves tissue engineering using iPSCs. Such an approach could eventually be used in humans and would allow autologous transplantation, thereby eliminating the problem of host rejection. The use of iPSCs will allow efficient differentiation into endothelial cells and other cardiac lineage cells, immune compatibility between donor and recipient tissues, and rapid transport of nutrients and waste products to new and developing tissue (via blood vessel formation). We hypothesize that a tri-cell patch composed of a network of iPSC-derived endothelial cells and other cardiac lineage cells will be effective for regrowth of neovasculature and myocardial tissue, which in turn could lead to improved cardiac function. In Aim 1, we will perform in vitro studies to characterize iPSC differentiation and define the optimal conditions for their directed differentiation into endothelial and cardiomyocyte cell lineages that will be suitable for development of a tri-cell patch to be used in cardiac repair. We will further enhance the angiogenic or myogenic potential of cardiac precursor cells, and determine whether preconditioning promotes differentiation of iPSCs into cardiac lineage cells. In Aim 2 we will determine whether a prevascularized cell patch will increase the retention and survival of iPSC-derived cardiac phenotypes after implantation leading to significant improvements in vascularity, perfusion, and cardiac function. Studies in Aim 3 will determine whether downregulation of fibrosis by manipulating subcellular pathways by over expression of adenylyl cyclases or specific fibrosis repressive microRNAs will influence the engraftment of a cardiac progenitor cell patch after myocardial infarction. These studies will provide new insights into the development of engineered iPSC-derived cardiac tissue patches as a viable therapy for cardiac muscle regeneration. PUBLIC HEALTH RELEVANCE: This project will investigate the effectiveness of prevascularized tri-cell patch composed of endothelial cells, myocytes, and other cardiac lineage cells derived from induced pluripotent stem cells (iPSCs) for their survival and engraftment after in vivo application on infarcted hearts.